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Changes
Introduced in V5.7-0
The following describes the most significant changes which have
occurred in the AST library between versions V5.6-1 and V5.7-0 (the
current version):
- The FitsChan class support for the IRAF-specific ``TNX'' projection has
been extended to include reading TNX headers that use a Chebyshev
representation for the distortion polynomial.
- The FitsChan class support for the IRAF-specific ``ZPX'' projection has
been extended to include reading ZPX headers that use simple or Chebyshev
representation for the distortion polynomial.
- A bug has been fixed in the FitsChan class that caused headers
including the Spitzer ``-SIP'' distortion code to be read incorrectly if no
inverse polynomial was specified in the header.
- A new attribute called PolyTan has been added to the FitsChan class. It
can be used to indicate that FITS headers that specify a TAN projection
should be interpreted according to the ``distorted TAN'' convention
included in an early draft of FITS-WCS paper II. Such headers are created
by (for instance) the SCAMP tool (http://www.astromatic.net/software/scamp).
- The PolyMap class now provides a method called
astPolyTran
that adds an inverse transformation to a PolyMap by sampling the forward
transformation on a regular grid, and then fitting a polynomial function
from the resulting output values to the grid of input values.
Programs which are statically linked will need to be re-linked in
order to take advantage of these new facilities.
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AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk
Copyright (C) 2009 Science \& Technology Facilities Council